Relations of the New Zealand Flora to that of Australia--General Features of the Australian Flora--The Floras of South-eastern and South-western Australia--Geological Explanation of the Differences of these Two Floras--The Origin of the Australian Element in the New Zealand Flora--Tropical Character of the New Zealand Flora Explained--Species Common to New Zealand and Australia mostly Temperate Forms--Why Easily Dispersed Plants have often Restricted Ranges--Summary and Conclusion on the New Zealand Flora _Pages_ 487-508 CHAPTER XXIII ON THE ARCTIC ELEMENT IN SOUTH TEMPERATE FLORAS European Species and Genera of Plants in the Southern Hemisphere--Aggressive Power of the Scandinavian Flora--Means by which Plants have Migrated from North to South--Newly Moved Soil as Affording Temporary Stations to Migrating Plants--Elevation and Depression of the Snow-line as Aiding the Migration of Plants--Changes of Climate Favourable to Migration--The Migration from North to South has been Long going on--Geological Changes as Aiding Migration--Proofs of Migration by way of the Andes--Proofs of Migration by way of the Himalayas and Southern Asia--Proofs of Migration by way of the African Highlands--Supposed Connection of South Africa and Australia--The Endemic Genera of Plants in New Zealand--The Absence of Southern Types from the Northern Hemisphere--Concluding Remarks on the New Zealand and South Temperate Floras _Pages_ 509-530 CHAPTER XXIV SUMMARY AND CONCLUSION The Present Volume is the Development and Application of a Theory--Statement of the Biological and Physical Causes of Dispersal--Investigation of the Facts of Dispersal--Of the Means of Dispersal--Of Geographical Changes Affecting Dispersal--Of Climatal Changes Affecting Dispersal--The Glacial Epoch and its Causes--Alleged Ancient Glacial Epochs--Warm Polar Climates and their Causes--Conclusions as to Geological Climates--How Far Different from those of Mr. Croll--Supposed Limitations of Geological Time--Time Amply Sufficient both for Geological and Biological Development--Insular Faunas and Floras--The North Atlantic Islands--The Galapagos--St. Helena and the Sandwich Islands--Great Britain as a Recent Continental Island--Borneo and Java--Japan and Formosa--Madagascar as an Ancient Continental Island--Celebes and New Zealand as Anomalous Islands--The Flora of New Zealand and its Origin--The European Element in the South Temperate Floras--Concluding Remarks _Pages_ 531-545 * * * * * {xix} MAPS AND ILLUSTRATIONS PAGE 1. MAP SHOWING THE DISTRIBUTION OF THE TRUE JAYS _Frontispiece._ 2. MAP SHOWING THE ZOOLOGICAL REGIONS _To face_ 31 3. MAP SHOWING THE DISTRIBUTION OF _PARUS PALUSTRIS_ _To face_ 66 4. A GLACIER WITH MORAINES (From Sir C. Lyell's _Principles of Geology_) 109